Abstract: A floor cleaning machine of the type having a fluid driven scrub brush utilizes fluid pressure for applying down force on the scrub brush to a floor surface being cleaned. The fluid pressure applied is controlled by a fluid pressure regulator which has a movable valve element and an electrical coil for controlling the position of the movable valve element. There is a feedback circuit for controlling current through the coil which includes a source of power and a pulse width modulation switching device. The switching device in turn is controlled by a comparison between the current sensed in the coil circuit and an operator set value for the desired current to provide a desired down force on the cleaning brush.

Abstract: A fishing reel comprising a circumferential drag system including a drum structure within which an expansion member rests. The expansion member carries at its circumference an O-ring brought against the interior surface of the drum structure upon expansion of the expansion element. In this manner, controlled adjustment of the radially outward expansion element establishes a given magnitude drag coefficient for the drag system.